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प्रश्न
State two properties that a substance should possess when used as a thermionic emitter.
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उत्तर
Two properties are:
(i) High melting point. (ii) Low work function.
संबंधित प्रश्न
Answer the following questions based on a hot cathode ray tube
Name the charged particles
What is thermionic emission?
In the following fig. shows a radioactive source S in a thick lead container. The radiations pass through an electric field between the plates P and Q. Complete the diagram to show the paths of α , β and γ radiations.
Why is the source S placed in a thick lead container?
What happens to the position of an element in the periodic table when it emits an alpha particle
An element P disintegrates by α - -emission and the new element suffers two further disintegrations, both by β -emission, to form an element Q. Explain the fact that P and Q are the isotopes.
State three ways of obtaining an electron-beam.
A radioactive nucleus \[\ce{^A_ZX}\] undergoes spontaneous decay in the sequence \[\ce{^A_ZX -> _{Z-1 }B -> _{Z-3}C -> _{Z-2}D }\], where Z is the atomic number of element X. The possible decay particles in the sequence are ______.
A radioctive sample decays `7/8` times its original quantity in 15 minutes. The half-life of the sample is ______.
In the following atoms, which one is a radioisotope? Give one use of this isotope.
O16, C14, N14, He4
